Exterior angles always add up to 360 degrees so for 30-gon each exterior angles is 12 degrees (360/30)
To get the interior angles you subtract 180 from 12 to get 168 degrees
the area is 180 cm. to find the perimeter you would do 15+15+14+14 to get 54 cm. So for area you do (l×w) which is 15×14=180.
Answer:
D. 11.8 cm
Step-by-step explanation:
This triangle is a 30°-60°-90° triangle. There is a shortcut to find the lengths of the sides of a 30°-60°-90° triangle. The longest side is the hypotenuse. The longest side is double the shortest side or, the shortest side is half the longest side. Here the longest side is 5, so the short leg (shortest side) is 2.5
The other shortcut is that the longer leg is the
short leg×sqroot3
Here, the short leg is 2.5, so the long leg is 2.5×sqroot3
Perimeter is all the sides added together.
5 + 2.5+ 2.5×sqrt3
Do the times first.
5 + 2.5 + 4.3
= 11.8
